New study reveals that exposure to outdoor artificial light at night is associated with an increased risk of diabetes

Diabetes is a critical public health problem in China, and the onset and progression of the disease is largely governed by behavioural and environmental risk factors. The nation's rapid urbanisation and economic growth has resulted in a dramatic increase in urban lighting, and the number of people exposed to it.

A new study published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]) finds that outdoor artificial light at night (LAN) is associated with impaired blood glucose control and an increased risk of diabetes, with more than 9 million cases of the disease in Chinese adults being attributed to light at night exposure.

The study used data from the China Noncommunicable Disease Surveillance Study. A total of 98,658 adults participated, undergoing interviews to collect demographic, medical, household income, lifestyle, education and family history information. The mean age of participants was 42.7 years and around approximately half were women.

Body weight and height of participants were measured to calculate BMI, and blood samples were taken to obtain levels of both fasting and postprandial (after meal) serum glucose, as well as glycated haemoglobin (HbA1c). This is a form of glucose bound to haemoglobin in red blood cells which acts as a moving average of blood sugar over the previous 8 to 12 weeks.